Herceptin (chemical name: trastuzumab) is a targeted therapy medicine used to treat HER2-positive breast cancer. Since 2005, the standard of care has been to give Herceptin for 1 year after surgery and chemotherapy to reduce the risk of recurrence (the cancer coming back) of early-stage, HER2-positive breast cancer.

Like most cancer treatments, Herceptin can cause side effects, including possible heart damage. So, researchers have been trying to find out if Herceptin could be given for a shorter time and still effectively reduce the risk of recurrence of early-stage, HER2-positive breast cancer.

The SOLD trial compared 1 year of Herceptin to 9 weeks of Herceptin. Women treated with 9 weeks of Herceptin had fewer heart problems, but shorter disease-free survival. Disease-free survival is how long the women lived without a cancer recurrence. The researchers recommended that 1 year of Herceptin remain the standard of care.

HER2-positive breast cancers make too much of the HER2 protein. The HER2 protein sits on the surface of cancer cells and receives signals that tell the cancer to grow and spread. About one out of every four breast cancers is HER2-positive. HER2-positive breast cancers tend to be more aggressive and harder to treat than HER2-negative breast cancers.

Herceptin works by attaching to the HER2 protein and blocking it from receiving growth signals. Herceptin, which is given intravenously, is used to:

treat advanced-stage, HER2-positive breast cancers

lower the risk of recurrence of early-stage, HER2-positive breast cancers after surgery and other treatments

Treatments given after surgery to reduce the risk of recurrence are called adjuvant treatments.

About the SOLD trial

The SOLD trial included 2,174 women diagnosed with early-stage, HER2-positive breast cancer:

The women’s ages ranged from 48 to 64 years.

98% of the women were white.

About 66% of the women were postmenopausal.

39% of the cancers were stage I.

49% of the cancers were stage II.

12% of the cancers were stage III.

66% of the cancers also were hormone-receptor-positive.

The women were randomly split into two treatment groups:

1,085 women received three cycles of Taxotere (chemical name: docetaxel) plus Herceptin for 9 weeks, followed by three cycles of fluorouracil, Ellence (chemical name: epirubicin), and Cytoxan (chemical name: cyclophosphamide).

1,089 women received Taxotere for 9 weeks, plus Herceptin for 1 year; after the 9 weeks of Taxotere this group also received three cycles of fluorouracil, Ellence, and Cytoxan.

So, the two groups received the same chemotherapy treatments. The difference was in how long the women were treated with Herceptin.

The median follow-up time was 5.2 years. This means that half the women were followed for a longer time and half the women were followed for a shorter time.

Overall, slightly more women treated with 1 year of Herceptin were alive with no recurrence after about 5 years. Disease-free survival rates were:

88.0% for women treated with 9 weeks of Herceptin

90.5% for women treated with 1 year of Herceptin

Rates of cardiac side effects, while low, were doubled among women treated with 1 year of Herceptin:

2% of women treated with 9 weeks of Herceptin had cardiac side effects.

4% of women treated with 1 year of Herceptin had cardiac side effects.

Most of the cardiac side effects were classified as congestive heart failure.

Chemotherapy plus Herceptin for 1 year should remain the standard of care

“Although the shorter regimen was associated with fewer cardiac toxic effects, there was little absolute difference in clinically important survival outcomes…in the overall assessment, chemotherapy plus 1 year of anti-HER2 therapy should remain the standard treatment,” the researchers wrote.

If you’ve been diagnosed with early-stage, HER2-positive breast cancer and will be treated with Herceptin, you may want to talk to your doctor about your personal risk of treatment-related heart problems. You might want to ask if visiting a cardiologist before treatment starts is a good idea for you. The cardiologist can evaluate your heart function and decide if you’re at risk of developing heart problems from breast cancer treatment. Other research suggests that heart medicines, such as beta blockers or ACE inhibitors, taken along with Herceptin may reduce the risk of serious heart damage. Together, you and your doctors can decide on the best treatment plan for your unique situation.